^36 Professor Agassiz on the Glacier Theory. 



to 55°, lived in Sicily in lat. 35° to 40° ; or, in other words, when 

 the climate of Greenland extended its frosts beyond Scotland, 

 when the mean temperature of the British Islands, in place of 

 being above + 8° (46° .4 F.) cent., scarcely reached zero, the 

 present climate of England, and of the north of Germany, 

 prevailed in those parts of Europe which are now the warmest, 

 and where the mean temperature exceeds + 16° (60° .8 F). 



I shall afterwards publish the details of these observations, 

 when they embrace a basis sufficiently complete to form an inti- 

 mately connected whole ; it is sufficient, for my purpose at 

 present, to have indicated the principal results of these re- 

 searches, which confirm the opinion of the former existence 

 of a climate much more rigorous than that which now exists 

 in Europe, by proofs independent of those derived from the 

 traces of ancient glaciers. Now, a climate so different, could 

 not have existed without exercising a marked influence on 

 organic life ; and it is thus that the Arctic faunas, in our tem- 

 perate regions, confirm as fully the existence of ancient gla- 

 ciers, as the presence of these same glaciers explains the 

 existence of northern animals ; and, nevertheless, the facts 

 which establish the presence of the one, have nothing in com- 

 mon with the facts which prove the presence of the other. 



III. Parallel Terraces. — The third order of facts is that of pa- 

 rallel terraces. This phenomenon is too well known to require 

 description. Justly valued memoirs have delineated these ter- 

 races in full detail ; and the publications of Macculloch, of Sir 

 T. Dick Lauder, and of Mr Darwin, are so well known, that I 

 shall confine myself to the task of establishing the connection 

 which I conceive there is between these facts and the existence 

 of glaciers in Scotland, without discussing the various theories 

 that have been proposed for their explanation. When I visited 

 the parallel roads of Glen Roy with Dr Buckland, we were con- 

 vinced that the glacial theory alone satisfies all the exigencies 

 of the phenomenon ; and, as this locality is the best known of all 

 those where parallel terraces have been observed, I may limit 

 myself to this example for the explanation of all the others. 

 The flanks of Glen Roy and Glen Spean exhibit horizontal 

 and continuous terraces one above the other, which preserve 

 completely their parallelism throughout their whole extent, 



